When should I expect the stock oil return line gasket/oring to volcano out of the block and dump all my oil onto the ground?

I had an '87 760T with which I got to enjoy this experience 10+ years ago. Engine/turbo was stock B230FT with a Garett t3. I had also implemented the glorious manual boost controller on this vehicle at a pressure rating I can't say for certain. All I know is it didn't detonate on me at the time The event occurred when I was going to pass a truck on the freeway, and when it kicked down a gear at WOT I saw a plume of white smoke billow behind me as all my oil flowed through the block and onto the asphalt/sprayed along the 3" exhaust.

I RTV'd the s#!t out of a new gasket on that 760 and it held up after that, but that car is long gone now.

Since then, I've recently acquired a decent stage 0 945, and cranked up the boost to 10ish psi (spikes to 11.5-12psi because of the shi#y nature of cheap MBC)

I am basically waiting for the same thing to happen again...

I know it is a known issue, so I'm curious about the details. Is this a "keep the PCV system clean and it's less of an issue" thing or is this a "I should expect this to fail when I push XXX manifold pressure" sort of thing?

Of course I can tap it and thread a barb fitting or AN fitting, but that's not a concern. I was hoping to educate myself and others on the nature of this problematic failure of stock assembly via this post.

In all that time did you service the oil separator referred to above? You will want to service it on this 940 if you haven't. I've had these seals fail and they make a mess. Never a failure like you describe though. It's straight forward to replace and if you use RTV make sure you use the special oil resistant type. Like what could be used on a differential gasket.

I rebuilt the entire engine in the 87 760, however I do not recall if I did any cleaning to the PCV back then. It is very likely I installed it as it was when I tore the engine apart to get machined. I swear I thought this was a known issue, but perhaps my sources didn't maintain the PCV system either... LOL!

I will do some homework on this and make that a priority for my '95 wagon. I have an IPD turbo cam to slap in as well. Word on the street is that will wake things up a little more, I just need to find/schedule a time to do it on the weekend.

For the oil separator, OE is best by far. Just take it off (way easier with intake manifold off), fill it with diesel, shake the crap out of it, drain, repeat. Repeat until it comes out as clean diesel, then reinstall with a new green viton oring.

Also, of you happen to get a new oil seperator box, be weary of the aftermaeket ones that separate where it is plasti welded together

I was cheap and got a 30 dollar aftermarket from FCP euro. I will probably swap in the aftermarket and clean the original, and if the aftermarket gives me any issues I have a backup. It should arrive this next week, as well as the viton o rings..

Anyway, went to change the oil today, and it's weeping from the problem area that caused me to start this thread. It seems to be the only source of oil leaking on this car, so crankcase pressure is a concern.

I switched the oil to 10w-30 synthetic high mileage. New mann filter and magnetic oil plug with a new copper seal. It was definitely due for a change, the oil coming out was black as death.

Definitely weeping oil out of this seal. I need to clean the PCV to make sure it's not the issue, but yeah, If I go this deep I'm threading the block for sure. Maybe I'll keep it European and make it metric G 1/4 fittings ;) I prefer BSPP over NPT amyway.

Also, of you happen to get a new oil seperator box, be weary of the aftermaeket ones that separate where it is plasti welded together

Only takes a few minutes with a soldering iron that has a tip you don't need to save. You use the iron to further weld the plastic seam together. Haven't had any issues out of the two that I did this with.

Well I finally tackled cleaning the PCV system 2 days ago. The box wasn't too bad, but the hard line that goes to the intake manifold was pretty built up with deposits. I got it all cleaned and reassembled with a new viton oring seal. While I was in there, I replaced all rubber vacuum lines with silicone, replaced the turbo intake hose with the IPD silicone one, and replaced all v belts. It took me about 5 hours, and the battery was disconnected the whole time, so my LH 2.4 ECU has reset itself.

That said, I either have a vacuum leak, or the ECU is still learning. It idles ok when cold but once it warms up it starts getting lopey, like surging from 600 to 900 rpm in a oscillating fashion. I'm going to try to check for leaks today, because I have driven it for 2 days and almost a quarter tank and it hasn't improved.

On the positive side of things, I checked under the car twice and no oil drips, so I think I solved my crankcase pressure issue.

When the car warms up, the ECU temp sensor triggers the EGR solenoid to open, putting vacuum on the EGR valve (via diaphragm.) I simply capped off the solenoid vacuum signal to the EGR valve and it runs/idles great. I think the EGR system has failed, possibly a ruptured diaphragm. I have it "bypassed" for now so I can actually drive the car without a massive vacuum leak when it comes to temperature.